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Finite closed coverings of compact quantum spaces

Piotr M. Hajac, Atabey Kaygun, Bartosz Zieliński (2012)

Banach Center Publications

We consider the poset of all non-empty finite subsets of the set of natural numbers, use the poset structure to topologise it with the Alexandrov topology, and call the thus obtained topological space the universal partition space. Then we show that it is a classifying space for finite closed coverings of compact quantum spaces in the sense that any such a covering is functorially equivalent to a sheaf over this partition space. In technical terms, we prove that the category of finitely supported...

Finite presentation and purity in categories σ[M]

Mike Prest, Robert Wisbauer (2004)

Colloquium Mathematicae

For any module M over an associative ring R, let σ[M] denote the smallest Grothendieck subcategory of Mod-R containing M. If σ[M] is locally finitely presented the notions of purity and pure injectivity are defined in σ[M]. In this paper the relationship between these notions and the corresponding notions defined in Mod-R is investigated, and the connection between the resulting Ziegler spectra is discussed. An example is given of an M such that σ[M] does not contain any non-zero finitely presented...

Finitely generated almost universal varieties of 0 -lattices

Václav Koubek, Jiří Sichler (2005)

Commentationes Mathematicae Universitatis Carolinae

A concrete category 𝕂 is (algebraically) universal if any category of algebras has a full embedding into 𝕂 , and 𝕂 is almost universal if there is a class 𝒞 of 𝕂 -objects such that all non-constant homomorphisms between them form a universal category. The main result of this paper fully characterizes the finitely generated varieties of 0 -lattices which are almost universal.

Finitely silting comodules in quasi-finite comodule category

Qianqian Yuan, Hailou Yao (2023)

Czechoslovak Mathematical Journal

We introduce the notions of silting comodules and finitely silting comodules in quasi-finite category, and study some properties of them. We investigate the torsion pair and dualities which are related to finitely silting comodules, and give the equivalences among silting comodules, finitely silting comodules, tilting comodules and finitely tilting comodules.

Finiteness of the strong global dimension of radical square zero algebras

Otto Kerner, Andrzej Skowroński, Kunio Yamagata, Dan Zacharia (2004)

Open Mathematics

The strong global dimension of a finite dimensional algebra A is the maximum of the width of indecomposable bounded differential complexes of finite dimensional projective A-modules. We prove that the strong global dimension of a finite dimensional radical square zero algebra A over an algebraically closed field is finite if and only if A is piecewise hereditary. Moreover, we discuss results concerning the finiteness of the strong global dimension of algebras and the related problem on the density...

Finiteness Theorems for Deformations of Complexes

Frauke M. Bleher, Ted Chinburg (2013)

Annales de l’institut Fourier

We consider deformations of bounded complexes of modules for a profinite group G over a field of positive characteristic. We prove a finiteness theorem which provides some sufficient conditions for the versal deformation of such a complex to be represented by a complex of G -modules that is strictly perfect over the associated versal deformation ring.

Finitistic dimension and restricted injective dimension

Dejun Wu (2015)

Czechoslovak Mathematical Journal

We study the relations between finitistic dimensions and restricted injective dimensions. Let R be a ring and T a left R -module with A = End R T . If R T is selforthogonal, then we show that rid ( T A ) findim ( A A ) findim ( R T ) + rid ( T A ) . Moreover, if R is a left noetherian ring and T is a finitely generated left R -module with finite injective dimension, then rid ( T A ) findim ( A A ) fin . inj . dim ( R R ) + rid ( T A ) . Also we show by an example that the restricted injective dimensions of a module may be strictly smaller than the Gorenstein injective dimension.

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